1. Field
Apparatuses and methods consistent with the present disclosure relate to an image forming apparatus and a method for controlling charging thereof, and more particularly, to an image forming apparatus for performing charging using a magnitude of a current provided to a photoreceptor without measuring a surface potential of the photoreceptor, and a method for controlling charging thereof.
2. Related Art
An image forming apparatus refers to an apparatus for printing print data generated by a print control terminal device such as a computer to print paper. Examples of the image forming apparatus may include a photocopier, a printer, a facsimile, or a multi-function peripheral (MFP) having functions of a photocopier, a printer, and a facsimile, complexly implemented therein as a single apparatus.
Recently, laser print type image forming apparatuses have been commonly used, and a printing operation of a laser print type image forming apparatus includes charging, exposing, developing, transferring, and fusing processes.
In the charging process of the printing operation, a contact charging scheme of charging a photoreceptor by bringing a roller type charging member into contact with the photoreceptor is widely used. The contact charging scheme for charging a photoreceptor may include a direct current (DC) charging scheme of applying only a DC voltage and an AC+DC charging scheme of overlapping a DC voltage and an alternating current (AC) voltage and applying the overlapped voltage to a charging member.
Here, the DC charging scheme is a method of performing a charging operation only with DC power, which causes less damage to a surface of a photoreceptor to lengthen lifespan of the photoreceptor and generates less discharge products, compared with the AC+DC charging scheme. However, a surface potential of the photoreceptor formed due to DC charging is not uniform, compared with that printed and formed through AC+DC charging.
The AC+DC charging scheme is a method of performing a charging operation using AC power together with application of DC power, obtaining high uniformity of a surface potential of a photoreceptor, and when AC having a voltage with a sufficiently high peak value is applied to a specific DC voltage, the photoreceptor is charged to have the same surface potential as that of the DC voltage. However, a large amount of discharge occurring between a charging member and the photoreceptor damages a surface of the photoreceptor to degrade lifespan of the photoreceptor.
Meanwhile, a DC charging scheme is widely used in terms of lengthening lifespan of a photoreceptor. However, it is very complicate and difficult to determine a DC voltage to be applied in consideration of an environment, resistance of a charging member, and lifespan of a photoreceptor to form a desired surface potential of the photoreceptor.
In a recent DC charging scheme, a separate sensor for measuring a surface potential of a photoreceptor may be used, but it is also very complicate and difficult to use a separate sensor to measure a surface potential of a photoreceptor amid the trend in which image forming apparatuses are increasingly reduced in size.